linux-kernel - Re: [PATCH 2/6] perf test: Use a test program in perf record tests

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Date:   Wed, 7 Sep 2022 16:24:41 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Namhyung Kim <namhyung@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ian Rogers <irogers@...gle.com>,
        linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 2/6] perf test: Use a test program in perf record tests

On 7/09/22 16:16, Adrian Hunter wrote:
> On 7/09/22 09:46, Namhyung Kim wrote:
>> If the system has cc it could build a test program with two threads
>> and then use it for more detailed testing.  Also it adds initial delay
>> of 3ms to profile a multi-threaded target.  This change make the test
>> failing but that's what we want to check for now.
>>
>> If cc is not found, it falls back to use the default value 'true'.
>>
>> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
>> ---
>>  tools/perf/tests/shell/record.sh | 58 +++++++++++++++++++++++++++++---
>>  1 file changed, 54 insertions(+), 4 deletions(-)
>>
>> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
>> index 40b087bfdb76..cea3c7b7e2cd 100755
>> --- a/tools/perf/tests/shell/record.sh
>> +++ b/tools/perf/tests/shell/record.sh
>> @@ -6,10 +6,18 @@ set -e
>>  
>>  err=0
>>  perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
>> +testprog=$(mktemp /tmp/__perf_test.prog.XXXXXX)
>> +testsym="test_loop"
>> +testopt="-D 3"
>>  
>>  cleanup() {
>>    rm -f ${perfdata}
>>    rm -f ${perfdata}.old
>> +
>> +  if [ "${testprog}" != "true" ]; then
>> +    rm -f ${testprog}
>> +  fi
>> +
>>    trap - exit term int
>>  }
>>  
>> @@ -19,9 +27,49 @@ trap_cleanup() {
>>  }
>>  trap trap_cleanup exit term int
>>  
>> +build_test_program() {
>> +  if ! [ -x "$(command -v cc)" ]; then
>> +    # No CC found. Fall back to 'true'
>> +    testprog=true
>> +    testsym=true
>> +    testopt=''
>> +    return
>> +  fi
>> +
>> +  echo "Build a test program"
>> +  cat <<EOF | cc -o ${testprog} -xc - -pthread
>> +#include <stdio.h>
>> +#include <unistd.h>
>> +#include <pthread.h>
>> +
>> +void test_loop(void) {
>> +  volatile int count = 1000000;
>> +
>> +  // wait for perf record
>> +  usleep(5000);
>> +
>> +  while (count--)
>> +    continue;
>> +}
>> +
>> +void *thfunc(void *arg) {
>> +  test_loop();
>> +  return NULL;
>> +}
>> +
>> +int main(void) {
>> +  pthread_t th;
>> +  pthread_create(&th, NULL, thfunc, NULL);
>> +  test_loop();
>> +  pthread_join(th, NULL);
>> +  return 0;
>> +}
>> +EOF
>> +}
>> +
>>  test_per_thread() {
>>    echo "Basic --per-thread mode test"
>> -  if ! perf record -o /dev/null --quiet true 2> /dev/null
>> +  if ! perf record -o /dev/null --quiet ${testprog} 2> /dev/null
>>    then
>>      echo "Per-thread record [Skipped event not supported]"
>>      if [ $err -ne 1 ]
>> @@ -30,13 +78,13 @@ test_per_thread() {
>>      fi
>>      return
>>    fi
>> -  if ! perf record --per-thread -o ${perfdata} true 2> /dev/null
>> +  if ! perf record --per-thread ${testopt} -o ${perfdata} ${testprog} 2> /dev/null
>>    then
>>      echo "Per-thread record [Failed record]"
>>      err=1
>>      return
>>    fi
>> -  if ! perf report -i ${perfdata} -q | egrep -q true
>> +  if ! perf report -i ${perfdata} -q | egrep -q ${testsym}
>>    then
>>      echo "Per-thread record [Failed missing output]"
>>      err=1
>> @@ -62,7 +110,7 @@ test_register_capture() {
>>      return
>>    fi
>>    if ! perf record -o - --intr-regs=di,r8,dx,cx -e cpu/br_inst_retired.near_call/p \
>> -    -c 1000 --per-thread true 2> /dev/null \
>> +    -c 1000 --per-thread ${testopt} ${testprog} 2> /dev/null \
>>      | perf script -F ip,sym,iregs -i - 2> /dev/null \
> 
> With the kernel patch:
> 
> https://lore.kernel.org/lkml/20220711180706.3418612-1-kan.liang@linux.intel.com/
> 
> I get:
> 
> Samples for 'dummy:HG' event do not have IREGS attribute set. Cannot print 'iregs' field.

We seem to need:


diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 13580a9c50b8d..959291903936a 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -411,7 +411,7 @@ static int evsel__do_check_stype(struct evsel *evsel, u64 sample_type, const cha
       int type = output_type(attr->type);
       const char *evname;
 
-       if (attr->sample_type & sample_type)
+       if (evsel__is_dummy_event(evsel) || attr->sample_type & sample_type)
               return 0;
 
       if (output[type].user_set_fields & field) {
diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh





> 
>>      | egrep -q "DI:"
>>    then
>> @@ -73,6 +121,8 @@ test_register_capture() {
>>    echo "Register capture test [Success]"
>>  }
>>  
>> +build_test_program
>> +
>>  test_per_thread
>>  test_register_capture
>>  
>